The Corner

New York Times Op-Ed: It Was a Mistake to Believe the Hockey Stick

Richard Muller, a professor of physics at Berkeley said it, not us. His point is that the warming pause wouldn’t be considered a big deal if it weren’t for the hockey stick:

As for the recent plateau, I predicted it, back in 2004. Well, not exactly. In an essay published online then at MIT Technology Review, I worried that the famous “hockey stick” graph plotted by three American climatologists in the late 1990s portrayed the global warming curve with too much certainty and inappropriate simplicity. The graph shows a long, relatively unwavering line of temperatures across the last millennium (the stick), followed by a sharp, upward turn of warming over the last century (the blade). The upward turn implied that greenhouse gases had become so dominant that future temperatures would rise well above their variability and closely track carbon dioxide levels in the atmosphere.

I knew that wasn’t the case. The planet warmed by 0.6 degrees over the prior 50 years, but occasional, unexplained temperature fluctuations of as much as 0.3 degrees countered the rise at times and resulted in apparent pauses. Some of the fluctuations might have been caused by shifting ocean currents related to the Gulf Stream and El Niño — the episodic appearance of unusually warm ocean temperatures along the west coast of South America.

And he quotes himself in that essay:

“Suppose . . . future measurements in the years 2005-2015 show a clear and distinct global cooling trend. (It could happen.) If we mistakenly took the hockey stick seriously — that is, if we believed that natural fluctuations in climate are small — then we might conclude (mistakenly) that the cooling could not be just a random fluctuation on top of a long-term warming trend, since according to the hockey stick, such fluctuations are negligible. And that might lead in turn to the mistaken conclusion that global warming predictions are a lot of hooey. If, on the other hand, we reject the hockey stick, and recognize that natural fluctuations can be large, then we will not be misled by a few years of random cooling.”


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